Eye check-up to detect Alzheimer's disease

They compared the density and thickness of these blood vessels in 133 healthy individuals, 37 people with mild cognitive impairment (sometimes a precursor to Alzheimer's disease) and 39 people with Alzheimer's disease. The differences in density were statistically significant after researchers controlled for factors like age, gender, and level of education. Typically, they can see a network of tiny blood vessels but researchers identified a change that could signal early Alzheimer's.

The Alzheimer's group had loss of small retinal blood vessels at the back of the eye. In addition, a specific layer of the retina was thinner in those with Alzheimer's.

The eye scan used in the study could reveal changes in tiny capillaries, most less than half the width of a human hair, before blood vessel changes show up on a brain scan, according to the study. Their study was published online today in Ophthalmology Retina, a journal of the American Academy of Ophthalmology.

The new findings couldn't have happened without a new scanning technology, called optical coherence tomography angiography (OCTA), that allows users to see in fine detail the structure of the back part of the eye.

Citing a previous research, Goudey said: "Examining the concentration of the peptide in an individual's spinal fluid provides an indication of risk decades before any memory related issues occur".

Prof Fekrat and colleagues said diagnosing Alzheimer's is a challenge.

Although preliminary work in this small sampling yielded results that are very promising, it was noted further study making use of a larger sampling is required to validate their findings and to develop a saliva test for the disease.

It would also give patients time to plan for the future with their families - while they still have their faculties, said the U.S. team. Such techniques to study the brain are invasive and costly.